The 20 school districts with the biggest demographic changes

New Jersey's students have become far more diverse over the past two decades.

In 1998, if you picked two random students out of the student body, the chances of the pair being the same racial and ethnic category were 42 percent. Today, they'd be 31 percent.

The change was led by a surge in Hispanic students, who went from 14 percent of the public school population in 1998 to more than a quarter of it in 2016.

Hispanic residents have a higher fertility rate than white residents, leading to their growth in the school-age population, said James Hughes, a Rutgers professor who specializes in demographic research.

"The immigrants coming here are looking for economic opportunity, so they tend to be young, fit and motivated," he said.

Both the Hispanic and Asian population, which increased from 6 and 10 percent, tend to move to places where there were "settlers there before them," Hughes said, leading to concentrations of minority population in certain areas, like New Brunswick.

"They want to move to places where there's a support structure — community groups, food stores, and places to send money back," he said. "They also move to areas where there's jobs for people with less education, and many of these districts have health services sectors that are growing."

NJ Advance Media reviewed the state's public school districts data between 1998, the earliest year available, and 2016 to find what districts changed the most during that time period. To calculate change, we totaled the percent change between the four major racial and ethnic categories — white, black, Hispanic, and Asian. Other races, which formed 2 percent of the 2016 student body, were excluded because of changes in how they were reported.

20. Fairview Borough

Fairview Borough in Bergen County had a total change of 79.1 percent from 1998 to 2016. During that time period, the district went from 905 students to 1388 students. The percent of Hispanic students grew 39 percent, while the percent of white students fell 38 percent.

19. Moonachie

Moonachie in Bergen County had a total change of 79.3 percent from 1998 to 2016. During that time period, the district went from 284 students to 315 students. The percent of Hispanic students grew 38 percent, while the percent of white students fell 40 percent.

18. Bogota

Bogota in Bergen County had a total change of 80.8 percent from 1998 to 2016. During that time period, the district went from 1161 students to 1089 students. The percent of Hispanic students grew 38 percent, while the percent of white students fell 41 percent.

18. South Hackensack

South Hackensack in Bergen County was tied with Bogota with a total change of 80.9 percent from 1998 to 2016. During that time period, the district went from 218 students to 275 students. The percent of Hispanic students grew 37 percent, while the percent of white students fell 40 percent.